Is the 7i92 less expensive? Do we even know the price of this USB->DB25 device?
What is really needed is for someone to write firmware for the common STM32F103 "Blue Pill". These have the hardware to do things like step gen and quadrature decode at MHz speeds and talk to the PC over SPI I2C or USB and cost under $3 from 100 different vendors. I use these for motion control when I can but not with Linux CNC. It is really "just a matter of software" but I'm not about to spend months of my time to save the cost of a 7i92. Take a look at the photo on the link below. I can imagine one of these connected via USB to a Pi4 or PC and then all those pins are available for machine control. Some of those pins can be connected to hardware counters that can counts steps or make pulses with no software. I've been able to read shaft encoders that are driven by an 11,000 motor and run the PID loop on the $3 part, not on the PC. But to use these with LCNC you have to write firmware and a matching HAL component. Mesa has already done this for their hardware saving me months of work for only $90. But still think how nice a $3 real-time LCNC interface card would be. ebay.com/itm/STM32F103C8T6-ARM-STM32-Minimum-System... <https://www.ebay.com/itm/STM32F103C8T6-ARM-STM32-Minimum-System-Development-Module-For-1pcs-V3X7/133446453174?hash=item1f120747b6:g:GxMAAOSwc59e8cuM> The argument that USB is "slow" is untrue. USB allows you to set on an "isochronous" channel with real-time continuous data flow. It will deliver data at a guaranteed rate. Think about a webcam sending 100 frames of video data per second and not dropping frames. That is way more then you need to drive a milling machine. Yes, you do get low perfomenace if the USB is emulating a serial port. but there as modes that allow real-time that are mostly intended for audio and visual data that could work well. This is for Windows not Linux but it works on all USB ports the same way. Take a look it is pretty much exaclty how you would use USB for real-time machine control https://docs.microsoft.com/en-us/windows-hardware/drivers/usbcon/transfer-data-to-isochronous-endpoints But again, it would take months to write a HAL component that connects to a $3 SMT32F103 part over a USB isochronous endpoint. Just perhaps this is what the guys in Poland did then they are selling a $2 chip burried in a $10 cable for $100 each? It could work. On Thu, Jul 23, 2020 at 9:52 AM John Dammeyer <jo...@autoartisans.com> wrote: > > This might have been mentioned on the MACH CNC group but the reality is that if you want LinuxCNC and two parallel ports the MESA 7i92 is less expensive and not tied to potential speed issues via USB. For example WIN-10 won't run the USB based Smooth Stepper but will run the Ethernet Smooth Stepper with MACH4. > > So for LinuxCNC at $89 the 7i92H is just overall a better deal. Or any of the MESA or PICO based products. For all the costs involved in CNC the truth is during the learning curve part the broken tool bits and trashed work is far more expensive but considered part of the costs. Ethernet is faster and less likely to have timing issues. > > My 2 cents. > > John > > > -----Original Message----- > > From: Dave Matthews [mailto:n36...@gmail.com] > > Sent: July-23-20 8:42 AM > > To: Enhanced Machine Controller (EMC) > > Subject: [Emc-users] Machmaker USB -> Parallel > > > > A link to a video for this thing showed up in my facecrap feed. It > > looks like a UC-100 only for LinuxCNC 2.9. They are demoing on a Pi > > 4. Has anyone got any experience with the Linumeric-LPT v1? Price > > and ordering are not shown on the site, you are directed to email > > them. > > > > Product Link - http://machmaker.pl/index.php?p=1_13 > > > > VIdeo - > > https://www.youtube.com/watch?v=txivr8j86t8&feature=youtu.be&fbclid=IwAR04UYfSGbRucny1aek0HVgJGrBkG0FiaxosNx_DQ > > iKoZXNBPOXl1Raue3A > > > > Dave > > > > > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users -- Chris Albertson Redondo Beach, California _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
